Python | Type conversion of dictionary items

The interconversion of data types is quite common, and we may have this problem while working with dictionaries as well. We might have a key and corresponding list with numeric alphabets, and we with to transform the whole dictionary to integers rather than string numerics. Let’s discuss certain ways in which this task can be performed. 

Method #1 : Using loop This problem can be solved using naive method by the use of loops. In this, we loop for each key and value and then typecast keys and value’s separately and returning the desired integral container. 

Python3

# Python3 code to demonstrate working of
# Type conversion of dictionary items
# Using loop

# Initialize dictionary
test_dict = {'1' : ['4', '5'], '4' : ['6', '7'], '10' : ['8']}

# printing original dictionary
print("The original dictionary : " +  str(test_dict))

# Using loop
# Type conversion of dictionary items
res = {}
for key, value in test_dict.items():
    res[int(key)] = [int(item) for item in value]

# printing result
print("Dictionary after type conversion : " + str(res))

Output : 

The original dictionary : {’10’: [‘8’], ‘4’: [‘6’, ‘7’], ‘1’: [‘4’, ‘5’]} Dictionary after type conversion : {1: [4, 5], 10: [8], 4: [6, 7]}

Method #2 : Using dictionary comprehension This task can be easily performed using single line shorthand using dictionary comprehension. This offers a shorter alternative to the loop method discussed above and hence recommended. 

Python3

# Python3 code to demonstrate working of
# Type conversion of dictionary items
# Using dictionary comprehension

# Initialize dictionary
test_dict = {'1' : ['4', '5'], '4' : ['6', '7'], '10' : ['8']}

# printing original dictionary
print("The original dictionary : " +  str(test_dict))

# Using dictionary comprehension
# Type conversion of dictionary items
res = {int(key):[int(i) for i in val]
       for key, val in test_dict.items()}

# printing result
print("Dictionary after type conversion : " + str(res))

Output : 

The original dictionary : {’10’: [‘8’], ‘4’: [‘6’, ‘7’], ‘1’: [‘4’, ‘5’]} Dictionary after type conversion : {1: [4, 5], 10: [8], 4: [6, 7]}

Method #3: Using map()
This task can also be performed using the map() function which allows us to map a function to each element of the iterable. This task can also be performed using the same.

Python3

# Python3 code to demonstrate working of
# Type conversion of dictionary items
# Using map

# Initialize dictionary
test_dict = {'1' : ['4', '5'], '4' : ['6', '7'], '10' : ['8']}

# printing original dictionary
print("The original dictionary : " +  str(test_dict))

# Using map()
# Type conversion of dictionary items
res = dict(map(lambda k_v:(int(k_v[0]), list(map(int, k_v[1]))), test_dict.items()))

# printing result
print("Dictionary after type conversion : " + str(res))
#This code is contributed by Edula Vinay Kumar Reddy

Output

The original dictionary : {'1': ['4', '5'], '4': ['6', '7'], '10': ['8']}
Dictionary after type conversion : {1: [4, 5], 4: [6, 7], 10: [8]}

Time Complexity: O(n)
Auxiliary Space: O(n)